Paraxial revision rod-to-rod connector

ABSTRACT

Disclosed herein are an orthopedic rod-to-rod connector and rod-to-rod connector assemblies for spinal fusion surgery. The rod-to-rod connector may include a first connector portion and a second connector portion. The first connector portion may have a first aperture configured to receive at least a portion of a bone-engaging screw and a first spinal rod. The second connector portion may be rotatably connected with the first connector portion and may include a second aperture to receive a second spinal rod. The second connector portion may be L-shaped and may include a set screw to control rotation of the first connector portion with respect to the second connector portion.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of the filling date of U.S.Provisional Patent Application No. 62/346,078, filed Jun. 6, 2016, thedisclosure of which is hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to spinal fusion surgery involving the useof pedicle (or lateral mass screws in the case of the cervical spine),and in particular, to devices and methods for adding additional spinalrod segments to already placed pedicle or lateral mass screw and rodconstructs.

The spinal column is a complex system of bones and connective tissuesthat provides support for the body and protects the spinal cord. Thesystem includes a number of vertebrae arranged to form a strongpillar-like structure, with each vertebral body cushioned byintervertebral discs placed between adjacent bodies. These discs areformed from a fibro-cartilage material and not only protect the spinalcolumn from compressive forces, but also allow for movement of thevertebral bodies with respect to each other.

Many spinal disorders result from the degeneration of the spinal discsand/or misalignment of the vertebral bodies. Spinal fixation is atechnique often used to correct such disorders by fusing together one ormore levels of vertebral bodies. For instance, pedicle or lateral massscrews are inserted in different vertebral bodies and linked togethervia spinal rods. This acts to immobilize the involved vertebral bodiesand may be coupled with the introduction of materials or implants thatcause the vertebral bodies to grow together.

However, at a later point, it may be necessary to fuse additionalvertebral bodies, especially in adjacent levels that may be negativelyimpacted by the initial fusion or otherwise subject of similar maladiesas the original level. Typically, these revision procedures involveremoving already implanted spinal rods, implanting additional pedicle orlateral mass screws and linking together all of the implanted pedicle orlateral mass screws with a new rod. Such a procedure takes time andremoval of previously implanted rods may be rather difficult.Furthermore, it may be that vertebral bodies at a different regions ofthe spine (e.g., cervical, thoracic or lumbar) may require fusiontogether. Given the differing size of the vertebral bodies at theselevels, it may be required to utilize differently sized and configuredpedicle or lateral mass screws, which in turn may make it difficult tolink the screws with a single spinal rod.

Therefore, there exists a need for improved devices and methods thatallow for easier pedicle or lateral mass screw revision surgery and/orallow for multiple regions of the spine to be fused utilizing pedicle orlateral mass screws.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to a rod-to-rod connector that isuseful in, inter alia, connecting two differently sized spinal rodstogether in a spinal fusion procedure. The connector of the presentinvention is particularly useful in revision procedures and/or inprocedures where multiple levels of the spine are fused together. Thevariability and easy connection provided by the connector construct aidsin simplifying such procedures.

One aspect of the present invention is an orthopedic rod-to-rodconnector including a first connector portion with a first apertureconfigured to receive at least a portion of a tulip of a screw (e.g., apedicle or lateral mass screw) and a second connector portion with asecond aperture and a third aperture. The third aperture is incommunication with a channel for receiving a spinal rod, and the secondconnector portion is rotatably coupled with the first connector portion.In accordance with the first aspect, an external surface of the tulipmay be received within the first aperture.

Other embodiments according to the first aspect may include a first setscrew placed through the first aperture and threadably coupled with thetulip. The first set screw may have an extension portion extendingthrough the first and second apertures and may be threadably coupledwith a nut. A second set screw may also be threadably coupled with thethird aperture and may extend into the channel Tightening of the nut mayprevent rotation of the first connector portion with respect to thesecond connector portion. The second connector portion may include anL-shaped portion defining the channel and a fourth aperture and adepression in communication with the channel. The L-shaped portion maydefine at least three points of contact on the spinal rod or may defineat least three surface contact regions on the spinal rod. The firstportion may include an extension received within the second aperture,and the extension may be a circumferential extension.

Another aspect of the present invention is an assembly including a screwportion for engaging a bone, a tulip connected to the screw portion, thetulip having a first channel, a first connector portion with a firstaperture receiving at least a portion of an external surface of thetulip, a second connector portion with a second aperture and a thirdaperture, the third aperture in communication with a second channel, thesecond connector portion rotatably coupled with the first portion, afirst spinal rod disposed within the first channel and a second spinalrod disposed within the second channel The orientation of the firstchannel and the second channel may be varied vertically with respect tothe screw portion such that the first and second spinal rods disposed inthe first and second channel may be co-planar or non-coplanar with atransverse plane of the screw portion.

Embodiments according to this aspect may include a first set screwplaced through the first aperture and threadably coupled with the firstchannel, the first set screw may have an extension portion extendingthrough the first and second apertures and may be threadably coupledwith a nut. A second set screw may be threadably coupled with the thirdaperture and may extend into the second channel that receives the secondspinal rod. Tightening of the nut may prevent rotation of the firstconnector portion with respect to the second connector portion. Theconnector portion may include an L-shaped portion defining the secondchannel and a fourth aperture and a depression in communication with thesecond channel. The L-shaped portion may define at least three points ofcontact on the spinal rod or may define at least three surface contactregions on the spinal rod. The first connector portion may include anextension received within the second aperture, and that extension may bea circumferential extension.

Yet another aspect of the present invention is an assembly including ascrew portion for engaging a bone, a tulip connected to the screwportion, the tulip having a first channel and a first aperture incommunication with the first channel, a first connector portion disposedover at least a portion of the tulip, the first connector portionincluding a second aperture in communication with the first aperture, asecond connector portion rotatably coupled with the first portion, thesecond connector portion having a third aperture in communication withthe first and second apertures, a second channel and a fourth aperturein communication with the second channel, a first spinal rod disposedwithin the first channel, a first set screw threadably coupled withinthe first aperture and in contact with the first spinal rod, the firstset screw including an extension portion extending outside of the first,second and third apertures, a nut threadably coupled to the extensionportion, a second spinal rod disposed within the second channel and asecond set screw threadably coupled with the fourth aperture and incontact with the second spinal rod.

According to other embodiments of this aspect, the tulip may bepolyaxially movable with respect to the screw portion. The tulip mayinclude first and second arms defining the first channel. The firstconnector portion may include first and second legs that cooperate withthe first and second arms. Tightening of the nut may prevent rotation ofthe first connector portion with respect to the second connectorportion. The second connector portion may include an L-shaped memberdefining the second channel The L-shaped member may further include afifth aperture extending orthogonal to the second channel. The secondchannel may define three points of contact with the second spinal rod ormay define at least three surface contact regions on the spinal rod.

Another aspect of the present invention may include an assembly with tworod-to-rod connectors connecting two spinal rods. The rod-to-rodconnectors may be attached to parallelly positioned spinal rods suchthat a first portion of a first spinal rod is disposed in the firstchannel of the first rod-to-rod connector and a second portion of thespinal rod is disposed in the second channel of the second rod-to-rodconnector. In another configuration according to this aspect, a firstand second portion of a first spinal rod may be disposed in a firstchannel of a first rod-to-rod connector and a first channel of a secondrod-to-rod connector respectively.

Yet another aspect of the present invention is a surgical methodincluding the steps of providing a first screw including a first spinalrod disposed therein, contacting a first portion of a connector with aportion of the first screw, rotating a second portion of the connectorwith respect to the first portion and disposing a second spinal rod in achannel of the second portion. The method may also include the furthersteps of inserting a first set screw through the first connectorportion, inserting a second set screw through the second connectorportion placing a nut over a portion of the first set screw andtightening the nut to prevent the rotation of the first connectorportion with respect to the second connector portion.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the subject matter of the presentinvention and of the various advantages thereof can be realized byreference to the following detailed description in which reference ismade to the accompanying drawings in which:

FIG. 1 is a perspective view of a rod-to-rod connector according to oneembodiment of the present invention connected with a pedicle screw.

FIG. 2 is another perspective view of the connector of FIG. 1.

FIG. 3 is an exploded view of the connector of FIG. 1.

FIG. 4 is a cross-sectional side view of the connector of FIG. 1connected with a pedicle screw and two spinal rods in a firstconfiguration.

FIG. 5 is a side view of construct of FIG. 4.

FIG. 6 is an enlarged view of the connector of FIG. 1.

FIG. 7 is a perspective view of the construct of FIG. 4 in a secondconfiguration.

FIG. 8 is side view of the construct of FIG. 7 in the secondconfiguration.

FIG. 9 is a perspective view of the construct of FIG. 4 attached toanother pedicle screw.

FIG. 10 is a top view of the construct of FIG. 9.

FIG. 11A is a perspective view of the connector of FIG. 1 connected witha pedicle screw and two spinal rods in another configuration.

FIG. 11B is a perspective view of the construct of FIG. 11A with tworod-to-rod connectors.

DETAILED DESCRIPTION

In order to develop an appreciation of the principles of the invention,several embodiments as presented in FIGS. 1-10 will be described in thefollowing written specification. The scope of the invention is notintended, however, to be restricted to the embodiments described below.It is also understood that the present invention includes alterationsand modifications to the illustrated embodiments and includes furtherapplications of the principles of the invention as would normally occurto one skilled in the art to which this invention belongs.

As is shown in FIGS. 1 and 2, an orthopedic rod-to-rod connector 10 isdisclosed as including two connector portions 12 and 14. The connectorportions are rotatably coupled to each other, in the manner discussedmore fully below. Connector portion 12 is designed to cooperate with apedicle screw 1 having a first spinal rod 50 disposed therein, andconnector portion 14 is designed to receive a second spinal rod 52. Inmany cases, this pedicle screw is an already implanted screw, but couldbe a screw implanted at the time of connector 10. For instance,connector 10 is specifically useful in a revision scenario where aseries of pedicle screws (or in the case of the cervical spine, lateralmass screws) linked via a spinal rod are already present in the body,but additional level(s) of fixation are required. However, the connectormay also be useful in connecting differently sized spinal rods, whererequired (e.g., across multiple regions of the spine). Connector 10 isshown in certain of the Figures cooperating with a pedicle screw 1. Thatdevice is typical of a standard pedicle or lateral mass screw andincludes a screw portion 3 that is polyaxially coupled with a tulip 5,and the tulip also preferably includes a U-shaped channel 7 defined byupstanding threaded arms 9 a, 9 b. Of course, the present invention canbe configured to cooperate with any known pedicle screw, lateral massscrew, hook or the like.

Connector portion 12 includes two legs 16 a, 16 b which are spaced aparta sufficient distance so as to receive a portion of tulip 5 and define atulip receiving aperture 18. More particularly, legs 16 a, 16 b areconfigured to receive portions of arms 9 a, 9 b of tulip 5. The legs mayinclude structures capable of cooperating with like structures of tulip5, for instance, projections that extend into channels or the like. Itis also noted that legs 16 a, 16 b are designed so as to create voids 17a, 17 b that do not conflict with a rod extending through channel 7. Thesmall voids 19 a, 19 b above voids 17 a, 17 b create space to properlyfit in different tulip heads. Connector portion 12 also includes a setscrew aperture 20 that is in communication with receiving aperture 18and channel 7, as well as a circular extension 22 that facilitates therotatable cooperation with connector portion 14 (best shown in FIG. 4).

Connector portion 14 includes an upper portion 30 that includes aconnection aperture 32 and a set screw aperture 34. Connection aperture32 is sized and shaped to receive extension 22 in a manner that enablesthe rotation of connector portions 12, 14 with respect to each other.Connection aperture 32 is in communication with set screw aperture 20,receiving aperture 18 and channel 7. This cooperation will be discussedmore fully below. Set screw aperture 34 is threaded and extends over anL-shaped portion 36 that extends below upper portion 30. L-shapedportion 36 defines a channel 38 which is in communication with set screwaperture 34. Again, this will be discussed in more detail below. As isbest shown in FIG. 6, L-shaped portion 36 includes surfaces 40 a-c thatdefine three points of contact with a rod 52 placed within channel 38.These three major points of intersection 40 a, 40 b and 40 c between thespinal rod and the surface provide for a strong fixation of the rodwithin the channel. In this manner, a three-point fixation mechanism anda set screw 56 placed through set screw aperture 34 secures the spinalrod 52 in the channel 38. Additionally, L-shaped portion 36 defines arod aperture 42 (best shown in FIGS. 1 and 2) that extends therethroughand allows for reception of the spinal rod 52 in a direction orthogonalto channel 38. Rod aperture 42 cooperates with a depression 44 formed insurface 40 c so as to enable the orthogonal placement of the rod 52.Although orthogonal orientation of the rod with respect to channel 38 isfacilitated in the design shown in the Figures, it is to be understoodthat it is within the scope of the present invention to allow for adifferent orientation. For instance, rod aperture 42 and depression 44could be situated to allow for placement of a rod at any angle withrespect to channel 38. Both the channel 38 and rod aperture 42 can besized to accommodate rods of varying diameters such as 3.5 mm, 4.5 mm,5.5 mm and 6.0 mm in the parallel and orthogonal alignments. In eitherconfiguration, the rods connected together via connector 10 can be ofvarying diameters. The connector 10 therefore, eases the implantationprocedure of connecting two rods in a revision scenario or otherwise.

In addition to connector 10 and pedicle screw 1, a construct accordingto the present invention includes set screw 54 and a nut 58. This isbest shown in FIGS. 4, 5 and 7-10. Spinal rod 50 is disposed withinchannel 7 and spinal rod 52 is disposed within channel 38 (either alongthe channel or orthogonal thereto). Set screw 54 is threaded withthreaded arms 9 a, 9 b of tulip 4 and extends into channel 7 so as tocontact spinal rod 50. As in a typical polyaxial pedicle or lateral massscrew design, tightening of set screw 54 bears on rod 50 which in turnprevents movement of screw portion 3 with respect to tulip 5. Set screw54 also includes an extension portion that extends through apertures 20and 32 and above upper portion 30 so as to be engageable with nut 58.Tightening of nut 58, not only ensures that connector 10 is held to thepedicle screws, but also prevents rotation of connector portions 12, 14with respect to each other. As best seen in FIG. 5, a centrallongitudinal axis 60 of channel 7 and a central longitudinal axis 62 ofchannel 38 are offset by a distance 64. However, distance 64 can beadjusted by moving channel 38 or channel 7 such that the axes 60 and 62may be co-planar along a transverse plane with respect to screw portion3. Furthermore, longitudinal axis 62 of channel 38 can also bevertically varied as shown by arrow 66 to orient spinal rod 52 at anyangle with respect to spinal rod 50. Vertical aligment flexibility isintended to allow rod alignment to match curvature of spine.

In one method of use, connector 10 is utilized in connection with thelast pedicle (or lateral mass) screw in a previously implanted pedicle(or lateral mass) screw construct when another level or levels of fusionare desired (i.e., a revision procedure). In such a case, the connectoris placed over the tulip of the pedicle (or lateral mass) screw, asdescribed above. Given that there is often not a lot of rod overhandfrom the last pedicle (or lateral mass) screw in the initial assembly,engagement with the original rod is often difficult. Thus, placement ofthe connector over the pedicle (or lateral mass) screw itself easesperformance of the procedure. The connector of the present inventionalso creates a strong connection point, which improves the overallstability of the resultant construct.

After placement of connector 10, one or more additional pedicle (orlateral mass) screws are then placed in the additional vertebral bodiesthat are desired to be fused to the previously fused bodies. Connectorportion 14 is then rotated with respect to connector portion 12 so as toplace it in the most suitable configuration for receiving a secondspinal rod for the additional level(s). FIGS. 4 and 5 depict a firstconfiguration in which the already implanted spinal rod and the newspinal rod extend along substantially parallel axes. In thisconfiguration, a rod placed within channel 38 extends along the axis ofthe channel FIGS. 7 and 8 depict a second configuration in which thespinal rods again extend along substantially parallel axes, but the rodplaced through aperture 42 extends orthogonal to the axis of the channel38. The first and second configurations essentially allow for adifferent offset distance between the rods. FIGS. 9 and 10 depict athird configuration in which the rods extend at an angle with respect toeach other. The rotatable nature of portions 12, 14 allows for thisangle to vary, and the flexibility of the placement of a rod withinchannel 38 allows for further variations in the resultant construct.This is especially beneficial where pedicle (or lateral mass) screws areoffset from each other along the spine. Connector 10 enables the rods tobe placed even where these offsets may be significant.

Referring now to FIGS. 11A and 11B, there is shown another arrangementof connector 10, wherein connector 10 is located around an interiorportion of two spinal rods 50 and 52 away from the ends of these spinalrods. As best shown in FIG. 11B, two connectors 10 and 10′ can also beused in a “quad rod” procedure, whereby two rods may be secured acrossvertebrae. A quad rod technique generally employs four rods instead oftwo rods across the vertebrae. A second rod is added to the main rod oneach side of the spinous process and connected by rod-to-rod connectorsto increase overall rigidity of the fixation assembly. As shown here, asecond rod 52 may be added to a main rod 50 on each side of the spinousprocess and connected by two rod-to-rod connectors 10 and 10′ to performa quad rod procedure. The rod-to-rod connectors may be oriented inopposite directions such that spinal rod 50 may be disposed in the firstchannel of connector 10 and the second channel 38′ of connector 10′ asshown in FIG. 11B. This allows for anchoring at least one screw portion3 to each spinal rod. Other configurations may have the rod-to-rodconnectors oriented in the same direction wherein spinal rod 52 may bedisposed in the first channel of the first rod connector and the firstchannel of the second rod connector. While two rod-to-rod connectors areshown in FIG. 11B, other embodiments may have multiple rod-to-rodconnectors attached to two or more spinal rods. Further connector 10 maybe used in conjunction with spinal fixation assemblies comprising spinalrod loops, spinal rod connectors and spinal rod reinforcers disclosed inU.S. Provisional Application No. 62/362,690, the disclosure of which ishereby incorporated by reference herein.

The connector of the present invention is also useful in situationswhere vertebral bodies across different regions of the spine are beingfused by a rod and screw construct. Typically, such constructs involvethe use of tapering spinal rods that allow for placement of the rod inpedicle screws sized for the different regions (or in the case of thecervical spine, within lateral mass screws). For instance, a constructextending between the thoracic and lumbar regions of the spine willinclude a rod with a smaller diameter end for reception within thepedicle screws placed in the thoracic region and a larger diameter endfor reception within the pedicle screws placed in the lumbar region. Aproblem that is often faced in such constructs is that the size and/ororientation of the vertebral bodies requires a level to be skipped. Suchregion spanning constructs have also been addressed by utilizing twodifferently sized rods that are connected via a different type ofrod-to-rod connector that again often requires the skipping of a level.Use of the connector of the present invention negates the need for suchlevel skipping. For instance, in the foregoing situations, connector 10can be placed over a pedicle screw (or a lateral mass screw) in theconstruct and engaged with one of the differently sized rods. Thus,every level can be provided with a pedicle screw and none need to beskipped.

The various components of the present invention can be constructed ofmany different materials, preferably materials suitable for implantationin the body. Such components must also be able to withstand the forcestypically present in a spinal fusion situation. For instance, it iscontemplated to form the various portions of a metallic material, suchas stainless steel or titanium. Of course, other materials may beutilized and different portions of the devices disclosed herein can beconstructed of different materials from each other. It is alsocontemplated to provide connectors of varying sizes/configurations foruse in connection with differently sized or configured pedicle (orlateral mass) screws and rods. The various connectors may be provided ina kit along with corresponding set screws, rods, etc. Of course, toolssuitable for implantation and fixation of the connectors according tothe present invention may also be provided. These may include drivers,clamps and other tools necessary to enable the proper application anduse of the connectors.

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It is therefore to be understood that numerousmodifications may be made to the illustrative embodiments and that otherarrangements may be devised without departing from the spirit and scopeof the present invention as defined by the appended claims.

1. An orthopedic rod-to-rod connector comprising: a first connectorportion with a first aperture configured to receive at least a portionof a tulip of a screw; and a second connector portion with a secondaperture and a third aperture, the third aperture in communication witha channel for receiving a spinal rod, wherein the second connectorportion is rotatably coupled with the first connector portion.
 2. Theconnector of claim 1, wherein at least a portion of an external surfaceof the tulip is received within the first aperture.
 3. The connector ofclaim 1, further comprising a first set screw placed through the firstaperture and threadably coupled with the tulip, the first set screwhaving an extension portion extending through the first and secondapertures and threadably coupled with a nut.
 4. The connector of claim1, further comprising a second set screw threadably coupled with thethird aperture and extending into the channel
 5. The connector of claim3, wherein tightening of the nut prevents rotation of the firstconnector portion with respect to the second connector portion.
 6. Theconnector of claim 1, wherein the second connector portion includes anL-shaped portion defining the channel and a fourth aperture and adepression in communication with the channel.
 7. The connector of claim6, wherein the L-shaped portion defines at least 3 points of contact onthe spinal rod.
 8. The connector of claim 1, wherein the first connectorportion includes an extension received within the second aperture. 9.The connector of claim 8, wherein the extension is a circumferentialextension.
 10. An assembly comprising: a screw portion for engaging abone; a tulip connected to the screw portion, the tulip having a firstchannel; a first connector portion with a first aperture receiving atleast a portion of an external surface of the tulip; a second connectorportion with a second aperture and a third aperture, the third aperturein communication with a second channel, the second connector portionrotatably coupled with the first portion; a first spinal rod disposedwithin the first channel; and a second spinal rod disposed within thesecond channel.
 11. The assembly of claim 10, further comprising a firstset screw placed through the first aperture and threadably coupled withthe first channel, the first set screw having an extension portionextending through the first and second apertures and threadably coupledwith a nut.
 12. The assembly of claim 10, further comprising a secondset screw threadably coupled with the third aperture and extending intothe second channel that receives the second spinal rod.
 13. The assemblyof claim 11, wherein the tightening of the nut prevents the rotation ofthe first connector portion with respect to the second connectorportion.
 14. The assembly of claim 10, wherein the connector portionincludes an L-shaped portion defining the second channel and a fourthaperture and a depression in communication with the second channel 15.The assembly of claim 14, wherein the L-shaped portion defines at least3 points of contact on the spinal rod.
 16. The assembly of claim 10,wherein the first connector portion includes an extension receivedwithin the second aperture.
 17. The assembly of claim 10, wherein thetulip includes first and second arms defining the first channel.
 18. Theassembly of claim 10, wherein the first connector portion includes firstand second legs that cooperate with the first and second arms.
 19. Theassembly of claim 10, wherein the tulip is polyaxially movable withrespect to the screw portion.
 20. An orthopedic rod-to-rod connectorcomprising: a first connector portion with a first aperture receiving atleast a portion of an external surface of a tulip of a screw; and asecond connector portion with a second aperture and a third aperture,the third aperture in communication with a channel for receiving aspinal rod, wherein the second connector portion is rotatably coupledwith the first connector portion.